Just added the wife's Audi to the cccdb, however her particular year of manufacture was not present, so given the short window of opportunity before Mosport, I've registered it as a 2004 (Audi S4 Avant) although it is actually a 2006 model.

To the best of my knowledge, there is no difference in engine, suspension or overall weight between an '04 and an '06 but I'll defer to the experts should there be a conflict.